---
id: CVE-2026-87733
title: >-
  An issue was discovered in the mirage-crypto-ec function before 2.2.0 for
  OCaml
summary: >-
  An issue was discovered in the mirage-crypto-ec function before 2.2.0 for
  OCaml. The ECDSA functions {P256,P384,P521}.Dsa.pub_of_octets accept 0x00, the
  encoding of the point at infinity, as a public key. With that public key,
  signatures…
severity: medium
cvss: 6.2
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'
cwe:
  - CWE-295
vendor: OCaml
product: mirage-crypto-ec
affected:
  - mirage-crypto-ec < 2.2.0
published: '2026-09-09'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T16:04:24.933'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-87733'
references:
  - url: 'https://osv.dev/vulnerability/OSEC-2026-13'
    label: cve@mitre.org
  - url: 'https://osv.dev/vulnerability/OSEC-2026-13'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-09T13:02:29.178538Z'
ingestedAt: '2026-09-09T05:00:01.767Z'
epss: 0.00105
epssPercentile: 0.01194
---

## Overview

An issue was discovered in the mirage-crypto-ec function before 2.2.0 for OCaml. The ECDSA functions {P256,P384,P521}.Dsa.pub_of_octets accept 0x00, the encoding of the point at infinity, as a public key. With that public key, signatures can be forged without a private key.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.